I searched for a thread like history of Soviet tank,to no avail.....I am interested how does replacing/upgrading AFVs practice works in US Army.I obtained R.P Hunnicutt book on Patton,which gave me the idea about introduction dates and various upgrades for Pattons.I had to search elsewhere for other vehicles.However,it is unclear to me how upgrading proceeded,what happened to older vehicles?

Example,M113 was produced in three improved version. A1 (1964); A2 (1979); A3 (1987) ...however,what happened to A1 when A2 introduced? They all were upgraded? NG received them? Scraped or transformed into new versions?Or M1 Abrams. All variants served together in,let's say,1992.Then,I think,remaining 105mm were upgraded to 120mm

M1, M1IP, and M1A1 were present at Knox for my OSUT training(JAN-MAY92). We had to know 105mm and 120mm breech block disassembly\reassembly, guards, loading, all that jazz.

Temporarily a Duece and a Half driver for a month were I was taught to drive stick on. I never drove stick before. A friend let me drive his stick pick up truck for five seconds afterward....Only five seconds. Stuff you can screw around on the tax payers dollar.

I drove a M113A2 filled with Air Force FM radios(ALO track) AUG1993-APR2004. It had laterals. Wasn't trained outside of playing Battlezone on how to drive one. First road march had a loose right latteral. They tossed me in it that day. Was scared that any sudden attempt to brake would cause me to go to a side and flip. Acceleration, was difficult to keep up with M1's. Floor it, watch out for any braking, lay off the gas, and try to coast instead of yanking back if I remember correctly.

Think it was M48A5 i saw at Hood late 1992-1993 on some field. Future range targets?Off topic, Chapparell was lined up going somewhere on Hood, summer 1992.M163 VADS still were doing gunnery. Think Dec1992. Looked like a stream of Star Wars laser blasters going downrange. Damn cool.

As for old 105mm M1's. They might still have a thousand needing upgrade. Think they are upgrading from M1A1s now. You might want to squint to see what's in the depots awaiting refurb.http://www.dtic.mil/...ta/Dunwoody.pdf

Or M1 Abrams. All variants served together in,let's say,1992.Then,I think,remaining 105mm were upgraded to 120mm

As far as I digged out informations, upgunning M1 is not an easy task, this is because there were fully developed two blocks of the M1:

Block 1 - M1 and M1IPBlock 2 - M1A1 and M1A2.

And now the interesting part, there are 3 versions of turret, I made my own typology to make things easier.

M1 use the Type 1 turret also known as "short turret", it have thinner front armor and there are probably other, minor differences. M1IP use Type 2 turret that is interim solution like the M1IP was when we consider whole tank. M1A1 and M1A2 use Type 3 turret, and then again even here are subtypes, because turrets of for example M1A2SEP have additional modifications.

Now the upgunning issue, if you want to upgun M1, you need to modernize it in to one of the Block II variants, which means a lot of cutting and welding work on the hull and... literally building new turret.

So even as Block I and Block II variants are part of the same vehicle family, in their basics they are also very different.

Actually the improvements that were made through they years expired or nearly expired vehicle SWaP-C characteristics, so the US Army is currently performing R&D program for ECP-1 (Engineering Change Proposal - 1) deep modernization program, that is intended to redesign or design a new all or nearly all internal components to make them more compact, lighter and power efficent, as well as to improve survivability by another armor modernization, some active protection solutions, and improve firepower by installing ammunition data link, which probably means replacing M256 with XM360E1/M360A1 that have data link as standard. But this is only list of currently accepted and needed improvements, by the end of this year or in 2014 there should be presented more specified list of improvements. Of course ECP-1 can be followed by ECP-2 and so on.

So actually besides a designation code the newer M1's have less and less in common with original design... but it seems to be normal for all weapons systems, when they receive improvements through their life cycle.

Thank you,very interesting. M48A5 was used by NG up to end of Cold War. Not sure when active Army sent them to reserve.

So,because of sheer numbers, all models continued active service alongside? I have a hint,because I read about initial force disposition for Desert Storm included M1 abd M1IP,but eventually only M1A1 saw action.

And what about M60 Pattons? They trouble me the most. I saw OOB for 1989,and M60A1 was in service,and Marines used M60A1(RISE/PASSIVE) with ERA in 1991.Were they withdrawn with A3 in 1997? And my initial curiosity was what have happened with original M60 and early M60A1s?

A new sighting device for the gunner was standardized in June 1978. Designated as the tank thermal sight (TTS), it replaced the gunner's M35E1 passive image intensification sight. The new device was independent of ambient light and utilized heat emitted by the target to form an image on a screen. More than twice as effective as the passive sight it replaced, the TTS could also sense targets through smoke, fog, or rain.The thermal sight consisted of a head assembly,the gunner's viewer, and a light pipe which enabled the tank commander to view the image on the gunner's screen. The new sight was installed in selected tanks staring in August 1979. These vehicles were then designated as the M60A3 (TTS).

Maybe it took them some time to effectively reach front units in Europe?However first M60A3 entered front line service barely 5 months earlier.

BTW did TTS required some major modifications to the tank, or it was just simple sights swap from the older to the new with TTS?

A a bit larger opening in the turret roof I believe is the only real difference between the 'A3 and 'A3 TTS. That and the power converter in the rear of the turret and of course losing the searchlight. Obviously there was quite a bit of difference for the gunner between M60A1 and the M60A3.

Thank you,very interesting. M48A5 was used by NG up to end of Cold War. Not sure when active Army sent them to reserve.

Aside from the two battalions in Korea, I don't believe any Regular Army units were ever equipped with M48A5s.

So,because of sheer numbers, all models continued active service alongside? I have a hint,because I read about initial force disposition for Desert Storm included M1 abd M1IP,but eventually only M1A1 saw action.

At least one and I believe two battalions from 1ID kept their M1IPs.

And what about M60 Pattons? They trouble me the most. I saw OOB for 1989,and M60A1 was in service,and Marines used M60A1(RISE/PASSIVE) with ERA in 1991.Were they withdrawn with A3 in 1997? And my initial curiosity was what have happened with original M60 and early M60A1s?

USMC never had the 'A3. They went straight from the M60A1 to M1A1, one of the battalions doing so in theater for ODS.

About 8500 M60A3s only about 1500 were new builds, the remainder were rebuilt from M60s and M60A1s.

It seemed, in the late '70s, that the Marines were getting M60s just as the Army was getting rid of them for M1s. Some of us wondered what the Army would get when they passed down the M1s. Had events not intervened, we might still be wondering...

It seemed, in the late '70s, that the Marines were getting M60s just as the Army was getting rid of them for M1s. Some of us wondered what the Army would get when they passed down the M1s. Had events not intervened, we might still be wondering...

In the late 1970s nobody was getting rid of their M60s for M1s, the first BN to transition to M1s was 2/5CAV 1st Cav Div (Though I understand they moved to 2AD, either just before or shortly after transition) in the fall of 1980. USAREUR tank BNs in 3AD started trading in their M60A1 RISE in July 1980 for M60A3s. Said transition quickly came to a 90 day halt because of some lingering problems with the tanks and because there wasn't enough special equipment and maunals go go around. 3ID was the first unit to field M1s in USAREUR in 1982. 8th ID in USAREUR wouldn't transition to M60A3s for two more years.

Sorry for being a nitpicker,but is it possible to trace when each of single models was upgraded,replaced or withdrawn from active Army and then National Guard? (only the end date,of course)

From your post I have understood large number of M60A1 were upgraded to M60A3,and I guess rest went to National Guard?And they were retired for good during the '90.

Or M1 and M1IP. They had a longer carrier than I have realized initially. At certain point they were transfered to NG,and presumably they now await scrapping.

I am basically interested in the fate of each model I listed above.

I would get that information, if possible, the same way you can, google it.

I can say this, the North Carolina NG received M1s concurrent with the Regular Army during the early 1980s. If memory serves NC received their M1s before any were fielded in Europe. A brigade of the NC NG rounded out the then 24th Inf Div which itself was part of the Rapid Deployment Force to SW Asia.

I think I was a bit generous as to how many M60A1s were rebuilt to M60A3, but it is still a much larger number than original build M60A3s. Maybe 4,000 to 6,000.

<ul class="bbc">
<li>M48A1 (until December 1979?)&nbsp;- <strong>Yes, many served as tanks in the Reserve components until the late 1970s.</strong></li>
<li>M48A3 - <strong>rebuilt from M48A1s</strong></li>
<li>M48A5 (October 1975-mid &#39;90) <strong>- rebuilt from remaining M48A1s/M48A2s and M48A3s</strong></li>
<li>M60 (fall of 1960-1963?)</li>
<li>M60A1 (1963-1972?) (basic version)</li>
<li>M60A1(AOS) (late 1972-1975))</li>
<li>M60A1(RISE) (1975-77?)</li>
<li>M60A1(RISE/PASSIVE) (1977-1997?)</li>
<li>M60A1 ERA (late &#39;80)</li>
<li>M60A2 &quot;Starship&quot; (1974-1981)<strong> - 540 built, retired, many chassis used for AVLB production</strong></li>
<li>M60A3 (May 1979-upgraded with TTS couple of months later?) <strong>- some new, many rebuilt from M60A1s</strong></li>
<li>M60A3 (TTS) (August 1979-1997)</li>
<li>M1 (1984-1992?)</li>
<li>M1IP&nbsp;&nbsp;(1984-1992?)</li>
<li>M1A1 (August 1985)</li>
<li>M1A1 HA (October 1988)</li>
</ul>
<p>Older US Army vehicles were either &quot;bumped&quot; down to reserve components (Army Reserve and Army National Guard), or rebuilt, or offered to various foreign military sales or military aid programs.&nbsp; M48s and M48A1s went to Jordan, Pakistan, etc.&nbsp; M48A2s went to Germany (some thence to Israel).&nbsp; A number of M48A3s were transfered to South Viet Nam.&nbsp; Due to a perceived tank shortage a number of remaining M48A1s, M48A2s and most M48A3s were rebuilt to M48A5s. Many M60A1s were rebuilt to M60A3s of various flavors.&nbsp; As the Cold War drew down a number of M48A5s and M60A3s were cleaned up and dumped into the ocean as artificial reefs.&nbsp; In a similar fashion a number of M1 variants have gone through several rebuild cycles (reportedly several thousand remain in storage for future rebuilding).&nbsp;</p>

11th ACR received their M60A3 Passives early in 1980, 2ACR received M60A3 TTS later in 1980. I'm not sure what the order of fielding was except that I don't believe 3ID ever received M60A3s, going straight to M1s from M60A1 RISE Passive in 1982, also I'm positive that 1AD received their M60A3 TTS in 1981 (I was there).

I would get that information, if possible, the same way you can, google it.

Bad odds then. That's why I have asked it here. Most result concern service dates entries,rarely a word about withdrawn. I continue searching,through...

I can say this, the North Carolina NG received M1s concurrent with the Regular Army during the early 1980s. If memory serves NC received their M1s before any were fielded in Europe. A brigade of the NC NG rounded out the then 24th Inf Div which itself was part of the Rapid Deployment Force to SW Asia.

I think I was a bit generous as to how many M60A1s were rebuilt to M60A3, but it is still a much larger number than original build M60A3s. Maybe 4,000 to 6,000.

So,because of sheer numbers, all models continued active service alongside? I have a hint,because I read about initial force disposition for Desert Storm included M1 abd M1IP,but eventually only M1A1 saw action.